1. 概述

本文主要对 PropertiesRouteDefinitionLocator 的源码实现。

• 蓝色部分 ：PropertiesRouteDefinitionLocator 。

2. PropertiesRouteDefinitionLocator

org.springframework.cloud.gateway.config.PropertiesRouteDefinitionLocator ，从配置文件( 例如，YML / Properties 等 ) 读取路由配置。代码如下 ：

public class PropertiesRouteDefinitionLocator implements RouteDefinitionLocator {

	private final GatewayProperties properties;

	public PropertiesRouteDefinitionLocator(GatewayProperties properties) {
		this.properties = properties;
	}

	@Override
	public Flux<RouteDefinition> getRouteDefinitions() {
		return Flux.fromIterable(this.properties.getRoutes());
	}
}

• #getRouteDefinitions() 方法，从 GatewayProperties 获取路由配置数组。

3. GatewayProperties

org.springframework.cloud.gateway.config.GatewayProperties ，从配置文件读取 ：

• 路由配置
• 默认过滤器配置。当 RouteDefinition => Route 时，会将过滤器配置添加到每个 Route 。

GatewayProperties 代码如下 ：

@ConfigurationProperties("spring.cloud.gateway")
@Validated
public class GatewayProperties {

	/**
	 * List of Routes
	 */
	@NotNull
	@Valid
	private List<RouteDefinition> routes = new ArrayList<>();

	/**
	 * List of filter definitions that are applied to every route.
	 */
	private List<FilterDefinition> defaultFilters = loadDefaults();

	private ArrayList<FilterDefinition> loadDefaults() {
		ArrayList<FilterDefinition> defaults = new ArrayList<>();
		FilterDefinition definition = new FilterDefinition();
		definition.setName(normalizeFilterName(RemoveNonProxyHeadersGatewayFilterFactory.class));
		defaults.add(definition);
		return defaults;
	}
}

• routes 属性，路由配置。通过 spring.cloud.gateway.routes 配置。以 YAML 配置文件举例子 ： 

spring:
  cloud:
    gateway:
      routes:
      # =====================================
      - host_example_to_httpbin=${test.uri}, Host=**.example.org

      # =====================================
      - id: host_foo_path_headers_to_httpbin
        uri: ${test.uri}
        predicates:
        - Host=**.foo.org
        - Path=/headers
        - Method=GET
        - Header=X-Request-Id, \d+
        - Query=foo, ba.
        - Query=baz
        - Cookie=chocolate, ch.p
        - After=1900-01-20T17:42:47.789-07:00[America/Denver]
        filters:
        - AddResponseHeader=X-Response-Foo, Bar

      # =====================================
      - id: add_request_header_test
        uri: ${test.uri}
        predicates:
        - Host=**.addrequestheader.org
        - Path=/headers
        filters:
        - AddRequestHeader=X-Request-Foo, Bar

• • 更多例子，点击 application.yml 查看。
• defaultFilters 属性，默认过滤器配置。通过 spring.cloud.gateway.default-filters 配置。以 YAML 配置文件举例子 ：

spring:
  cloud:
    gateway:
      default-filters:
      - AddResponseHeader=X-Response-Default-Foo, Default-Bar
      - PrefixPath=/httpbin